The peace process in Northern Ireland offers hope for other parts of the world trying to end conflict, former prime minister Tony Blair has said.
Reflecting on the 15th anniversary of the Good Friday Agreement he helped broker, Mr Blair said he believed the settlement achieved in the region would bring lasting peace. But he warned that political problems would still have to be overcome in the future.
"Fifteen years ago, when I came to Stormont, there was little expectation of a deal being done," said Mr Blair, who has hailed the 1998 accord as one of his government's greatest achievements in power.
"The peace process was in turmoil. But because of the will of the people in Northern Ireland, that historic Good Friday signalled the start of a peaceful future.
"Now as I travel to different parts of the world, what happened in Northern Ireland is something that immediately connects with people. It brings hope for other conflicts - from Africa to the Middle East - that a situation that once seemed so bleak can be resolved.
"There will be political crises, and there will be continuing problems, but I firmly believe that Northern Ireland will not return to the times of the Troubles. The gains of peace are visible and clear, and there is an overwhelming desire from the people for this to remain."
The Ulster Unionist Party (UUP) and nationalist Social Democratic and Labour Party (SDLP) were the two biggest parties in Northern Ireland at the time of the agreement. In the years since their influence has waned and the DUP and Sinn Fein have eclipsed them as the major parties within their respective communities.
Current UUP leader Mike Nesbitt accused Stormont's two main players of failing to deliver on the achievements of 1998.
"Yes, we have come a long way from where we were 15 and 20 and 25 years ago," he told an audience of young people at an event in east Belfast. "But maybe it's time to stop talking about what we have achieved and focus instead on what we have failed to achieve."
Mr Nesbitt told the assembled school children: "I can only conclude that, so far, we have yet to deliver a country properly at peace with itself."